A Self-Calibrating SDR for High Fidelity Beam- and Null-forming Arrays

TL;DR

This paper introduces a self-calibrating SDR architecture that enhances null forming accuracy in antenna arrays, crucial for spectrum-sharing and anti-jamming, validated through simulation and real-world experiments.

Contribution

The work presents a novel self-calibrating SDR design specifically for high-fidelity null forming, addressing phase and gain mismatch issues in antenna arrays.

Findings

Effective null suppression demonstrated in simulations.

Experimental validation on SDR platform from 3.0 to 3.5GHz.

Improved robustness against RF chain mismatches.

Abstract

Null forming is increasingly essential in modern wireless systems for spectrum-sharing, anti-jamming, and covert communications in contested and congested environments. Achieving deep nulls, however, is far more demanding than conventional beam steering: nulls are intrinsically narrow, and even small phase, timing, or gain mismatches across RF chains can significantly degrade suppression. This work develops and validates a self-calibrating SDR architecture tailored for high-fidelity null forming using a compact reference transmitter directionally coupled to the antenna feeds. We demonstrate the effectiveness of the approach through simulation and experimental measurements on an SDR platform operating from 3.0 to 3.5GHz, a band of growing importance for Department of Defense spectrum-sharing initiatives.